OS Linux Mint 18.1
Libre Office 5.2.4.2
Language packs needed Greek and Italian (already downloaded from official site)
On most GNU/Linux distros you’re not meant to install the distro type-specific data distributions (in Debian-like systems such as Ubuntu (and Linux Mint, which is a refined Ubuntu), the DEB files), but use the distro-specific repos. This system makes installing and updating data on the computer a breeze (since the package management system keeps the versions, if they’re correctly updated onto the repos, matched for you), more or less, but without using Launchpad PPAs you’re at the mercy of the devs to keep up with latest versions which commonly is questionably done, but even the PPAs don’t guarantee anything. The guarantee is you can get the source code and compile it yourself.
Help packages start with libreoffice-help-.
Language packages start with libreoffice-l10n-.